Process eoe bleaching barytes



Patented June 12, 1923.

LORENZ KNEEDLES AYERS, OF ST LOUIS, MISSOURI.

PROCESS FOR BLEACHING BARYTES.

No Drawing.

To all whom it may concern:

Be it known that I, LonnNz K. Arnns, a citizen of the United States, residing; at St. Louis, in the State of Missouri, have invented new and useful Improvements in the Processes for Bleaching Barytes, of which the following is a specification.

This process relates to the processes of bleaching barytes by means of a solution of sulphuric acid under pressures greater than atmospheric and has for its object to render the process more expeditious and considcrably cheaper.

Bleaching barytes by means of sulphuric acid solutions has heretofore been effected entirely at atmospheric pressure. Hooded tanks, stirred and heated by direct steam, or mechanically stirred and heated With steam coils, or combinations of these have been generally used.

Instead of depending only upon the temperature attained by atmospheric pressure, Which is approximately 210 IQ, I employ, to assist the bleaching of the barytes additional pressures and hence higher temperatures.

Furthermore it has been the practice in some plants, to use hydrochloric acid in considerable quantities to bleach the barytes. l have found that large quantities of hydrochloric acid causes the color of the product to be considerably inferior to that produced from sulphuric acid alone, nevertheless the rate of bleaching is considerably increased by its presence. I have found also that very minute quantities of hydrochloric acid, approximately .1% mixed With the sulphuric acid solutions, greatly accelerates the reaction and does not seem to interfere with the quality of the product. I limit myself to no set percentage of mixed hydrochloric and sulphuric acids solutions notwithstanding.

In bleaching barytes by my process I use Application filed April 15, 1922.

Serial No. 553,166.

an acid proof tank agitated by stirrers, live steam, or pumps. The tank is heated by lead or Duriron radiation units, either externally or internally. In this vessel I place my mixture of ground barytes and Water and add to it a specific Weight of sulphuric acid, depending on the iron content of barytes. This mixture is rapidly heated by direct and indirect steam heat at the same time being violently agitated. When the min ture is subjected to pressure the temperature rapidly rises until it is sufliciently high to show a rapid increase in the rate of bleaching. I used 110 pounds pressure n my heating units and 80 pounds internal pressure on my bleaching solution. This gave an approximate temperature of 320" F. in my bleaching solution. Although this gave excellent results showing a remarkable increase in the rate of bleaching and a considerable saving in acid, I confine myself to no specific pressure higher than atmospheric or to no specific temperature.

By this means bleaching being rendered very much more energetic it is effected with a considerably smaller quantity of the bleaching agent, in other Words, sulphuric acid.

I claim:

1. The process of bleaching barytes consisting in subjecting the ground barytes to the bleaching action of sulphuric acid solutions under pressures greater than atmospheric.

2. The process of bleaching barytes consisting in subjecting the ground barytes to the bleaching action of sulphuric acid solutions containing a small percentage of by drochloric acid under pressures greater than atmospheric.

LORENZ KNEEDLES AYERS. 

